Answer & Explanation
This rhythm strip actually has four premature beats – all are PVCs (premature ventricular contractions). You can be assured of this diagnosis because the beats are dissociated from the sinus rhythm – that is, the sinus rhythm continues through the rhythm strip, the early complex does not reset the sinus metronome as would an early atrial depolarization. Thus the early beat must be ventricular in origin. Recognizing dissociation of a PVC is simply another way of saying that there is a “fully compensated pause” – the sinus beat comes back right on time.